Chlorination of naphthalene



0t 31, 1933- R. ENGEL'HARDT 1,933,422

CHLORINATION OF. NAPHTHALENE Film1 Dec. 1'7, 1930 Patented Oct. 3l, 1933Y l PATENT OFFICE CHLORINATION OF -NAPHTHALENE Rudolf Engelhardt, Leverkusen-on-the-Rhlne, Germany, assignor to I. G. Farbenindustrie Aktiengesellschaft, Germany Application 'netember 17, 1030 serial No. 503,031

3.- Claims.

The present invention relates to the manufacture of chlorinated naphthalene of a waxlike nature.

In accordance with the present invention.

5 valuable masses of a wax-like nature of a chlorine content between about 46 and- 60%, that is to say, between about '3 and 5 chlorine atoms in the naphthalene molecule, are prepared by starting the chlorination process at a temperature of about\5 to about 10 C. above the melting point of naphthalene, then gradually lowering the temperature down to at least 30 C.,

simultaneously introducing chlorine into the melt, which temperature .of 30 C. is to be reached when about 1 chlorine atom has entered .the naphthalene molecule. Then again the temperature is slowly raised, while continuing the passing in of chlorine in such a manner that at about at most 50 C. 2 chlorine atoms have en- A tered the vnaphthalene molecule, at about 65 C.v 21/ chlorine atoms, and completing the chlorwination at a temperature of about 5 to 10 C. above the melting point of the reaction mixture. The chlorination is interrupted as lsoon as a 25 cooled test portion shows the desired wax-like consistency; that is, when about 3 to 5 chlorine atoms have entered the naphthalene nucleus, the whole chlorination process thus being 'performed at temperatures below 130 C.

In the annexed diagram curve I indicates the melting points ofchlorinated naphthalene, curve II indicates the lower limit o'f the chlorination temperature, said. curve indicating a range of temperatures-5 C. above the melting point of the chlorination product at any stage bfchlorination, while curve III is a temperature curve indicating the upper limit which is not to be exceeded at the specific chlorine contentstatedeon the absciss of the diagram. It, shall be `mentioned that`theoretical1y the whole. chlorination process shoulrLbe performed at temperatures about 5 to about 10 C.'above the melting point of the reaction mass, but as is to be seen from the curve of the melting pQints, when working in this manner a cooling down to about minus 25 C. would be necessary which would. render the process cumbersome. We therefore prefer to usea lower limit of about +30 C. The whole range of temperatures being taken into consideration for the purpose of the invention is to be seen from the annexed dia Example-20 parts of antimony trich'loride 65 are added to 2000 parts of naphthalene.. well mixed and the mass is fused. In the course of 10 hours 4400 parts of chlorine are led in, the temperature being kept along the broken line of curve IV of the annexed drawing. Air is then forced-through the melt for some time after which it can be used directly or distilled under reduced pressure.

I claim: 1. The process of chlorinating naphthalene which comprises continuously introducing chlorine vinto the molten reaction mass, maintaining the temperature between about 5 to about 10 C. above the melting point in each stage of the chlorination and a temperature indicated by a curve which follows the same general slope of the melting point curve and which gradually increases from 10 C. above the melting point curve at 80 C. to 60 C. above the melting point curve at 30 C. when one chlorine atom has S5 entered the molecule and 4which gradually de` creases again to about 22 C. above the melting point cu'rve an about V40 C. when 21/2 chlorine atoms have entered the molecule and to at *the most 15 C. above the melting point curve at a 90 'temperature of at least. 70 C. when at least 3 chlorine atoms have entered the molecule, until a. test portion shows; when cooled, the consistency of a Wax.

2. A process as claimed in claim l, in which V` the chlorination is performed with the addition L of a catalystof the group consisting of anti-v mony,'phosphorus, sulfur, iodine and their chlorine compounds.

3. A process as claimed in claim 1, in which the chlorination is performed with the addition of antimony trichloride as catalyst.

RUDOLF ENGELHARDT.

gram, the hatched area covering said interval of temperatures,

Furthermore, I have found that my new procggs may be carried out in the presence of a 4chlo 

